This begs the question: Scanning the NFL landscape, which team suffered the biggest loss of this offseason?

Ian Rapoport NFL.com

Cardinals will miss Horton's defensive guidance

The biggest loss of the offseason came on the sidelines, not on the field. The Arizona Cardinals should be much improved as a team this year, with a new head coach in Bruce Arians and a new quarterback in Carson Palmer. Yet, on the defensive side of the ball, losing coordinator Ray Horton -- a budding star -- stings. His principles and scheme were what helped Arizona get off to a 4-0 start without much of an offense last season. His defense made the Cards frustrating to play.

I'm not saying that Horton's replacement, Todd Bowles, won't be effective in Arizona, or that the team won't do well. But it might take some time for Bowles to replicate the success Horton had.

Albert Breer NFL.com

Arians leaves big shoes to fill with Colts

The Indianapolis Colts will miss former offensive coordinator Bruce Arians. The good news is that Andrew Luck is the quarterback in Indy, and there was a ready-made replacement to pluck from the college ranks: Pep Hamilton, Luck's old coordinator at Stanford. The bad news is that Arians, as he often does in his work with young players, set the bar awfully high last season, and it's not good for any quarterback to have to go through turnover at offensive coordinator. (See: Smith, Alex, and Campbell, Jason.)

I still believe Luck will finish 2013 as one of the game's five or six best quarterbacks. I just think it'll be a little harder to get there, and there might be a few more bumps along the road this time.

Gil Brandt NFL.com

Everyone overlooked Backus throughout his 12-year career, but Detroit will feel that loss

The easy answer here would be to go with someone like Wes Welker, but I'm going to highlight one of those guys who is taken for granted until he's no longer around: longtime Detroit Lions left tackle Jeff Backus, who retired this offseason.

Picked 18th overall by the Lions in the 2001 NFL Draft, Backus became an immediate contributor, starting the first 186 games of his career. He didn't miss a start until the Thanksgiving game last season -- after which he came back to start the final five games. That kind of longevity and durability is unheard of, really.

Though Backus never went to a Pro Bowl, the Lions knew when they went to training camp every year that they had a solid left tackle. Through most of his career, he was a very good football player on a mediocre team. And I think if you talk to Lions quarterback Matthew Stafford, he'll tell you that the reason he could throw for 5,000 yards a year was because of Backus' ability to block the back-side defensive end. Now that he's gone, I think the Lions will realize how good and efficient Backus was.

Jason Smith NFL.com

Ravens will find life tough without Reed and Lewis

This season, the Ravens will find out who's irreplaceable. Forget about finding another Ray Lewis AND Ed Reed in a minute, because in fact they won't be here in a minute. Or ever. You're talking about two of the best players in the history of the game at the linebacker and safety positions, respectively, and while they both slowed down in recent years, Lewis' retirement and Reed's departure via free agency easily qualify as the biggest losses any team suffered in the offseason. Until the very end, Lewis and Reed put the teeth in Baltimore's defense, and they still influenced games in big moments (like when Reed personally saved approximately 11 points with various individual efforts in Super Bowl XLVII).

Every offense still had to account for both players prior to every snap. Now, when any quarterback playing Baltimore looks across the line, he won't see Reed and Lewis in his field of vision -- and his confidence meter should rise. The image of this defense as the biggest, baddest unit in the game has disappeared. Teams will attack the Ravens more frequently, and let's face it -- offenses will play "faster" against them than they ever have. To the left, to the left ...

Adam Rank NFL.com

Colts could struggle without Arians

The Indianapolis Colts could be primed for a letdown this season. Every year, there seems to be one team that plays above its level, only to take a step back the next season (at least in terms of the win-loss record). And the Colts are good candidates to do just that.

Yes, they won a lot of close and emotional games last season, but the biggest reason to expect a step back might be the loss of Bruce Arians, who deserves much credit in the development of Andrew Luck. The Colts will miss his leadership this year.